PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> When attempting to set the data type on multiple columns in a single sql
> where the columns have indexes, the alter call fails. This previously worked
> on 9.6.6.
Thanks for the report! I believe this is the same issue already reported
and fixed at
https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=da1041fc3
At least, your example doesn't fail for me on 9.6 branch tip.
regards, tom lane